1 /*
2  * An implementation of key value pair (KVP) functionality for Linux.
3  *
4  *
5  * Copyright (C) 2010, Novell, Inc.
6  * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License version 2 as published
10  * by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
15  * NON INFRINGEMENT.  See the GNU General Public License for more
16  * details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21  *
22  */
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 
25 #include <linux/net.h>
26 #include <linux/nls.h>
27 #include <linux/connector.h>
28 #include <linux/workqueue.h>
29 #include <linux/hyperv.h>
30 #include <asm/hyperv-tlfs.h>
31 
32 #include "hyperv_vmbus.h"
33 #include "hv_utils_transport.h"
34 
35 /*
36  * Pre win8 version numbers used in ws2008 and ws 2008 r2 (win7)
37  */
38 #define WS2008_SRV_MAJOR	1
39 #define WS2008_SRV_MINOR	0
40 #define WS2008_SRV_VERSION     (WS2008_SRV_MAJOR << 16 | WS2008_SRV_MINOR)
41 
42 #define WIN7_SRV_MAJOR   3
43 #define WIN7_SRV_MINOR   0
44 #define WIN7_SRV_VERSION     (WIN7_SRV_MAJOR << 16 | WIN7_SRV_MINOR)
45 
46 #define WIN8_SRV_MAJOR   4
47 #define WIN8_SRV_MINOR   0
48 #define WIN8_SRV_VERSION     (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
49 
50 #define KVP_VER_COUNT 3
51 static const int kvp_versions[] = {
52 	WIN8_SRV_VERSION,
53 	WIN7_SRV_VERSION,
54 	WS2008_SRV_VERSION
55 };
56 
57 #define FW_VER_COUNT 2
58 static const int fw_versions[] = {
59 	UTIL_FW_VERSION,
60 	UTIL_WS2K8_FW_VERSION
61 };
62 
63 /*
64  * Global state maintained for transaction that is being processed. For a class
65  * of integration services, including the "KVP service", the specified protocol
66  * is a "request/response" protocol which means that there can only be single
67  * outstanding transaction from the host at any given point in time. We use
68  * this to simplify memory management in this driver - we cache and process
69  * only one message at a time.
70  *
71  * While the request/response protocol is guaranteed by the host, we further
72  * ensure this by serializing packet processing in this driver - we do not
73  * read additional packets from the VMBUS until the current packet is fully
74  * handled.
75  */
76 
77 static struct {
78 	int state;   /* hvutil_device_state */
79 	int recv_len; /* number of bytes received. */
80 	struct hv_kvp_msg  *kvp_msg; /* current message */
81 	struct vmbus_channel *recv_channel; /* chn we got the request */
82 	u64 recv_req_id; /* request ID. */
83 } kvp_transaction;
84 
85 /*
86  * This state maintains the version number registered by the daemon.
87  */
88 static int dm_reg_value;
89 
90 static void kvp_send_key(struct work_struct *dummy);
91 
92 
93 static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
94 static void kvp_timeout_func(struct work_struct *dummy);
95 static void kvp_host_handshake_func(struct work_struct *dummy);
96 static void kvp_register(int);
97 
98 static DECLARE_DELAYED_WORK(kvp_timeout_work, kvp_timeout_func);
99 static DECLARE_DELAYED_WORK(kvp_host_handshake_work, kvp_host_handshake_func);
100 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
101 
102 static const char kvp_devname[] = "vmbus/hv_kvp";
103 static u8 *recv_buffer;
104 static struct hvutil_transport *hvt;
105 /*
106  * Register the kernel component with the user-level daemon.
107  * As part of this registration, pass the LIC version number.
108  * This number has no meaning, it satisfies the registration protocol.
109  */
110 #define HV_DRV_VERSION           "3.1"
111 
kvp_poll_wrapper(void * channel)112 static void kvp_poll_wrapper(void *channel)
113 {
114 	/* Transaction is finished, reset the state here to avoid races. */
115 	kvp_transaction.state = HVUTIL_READY;
116 	tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event);
117 }
118 
kvp_register_done(void)119 static void kvp_register_done(void)
120 {
121 	/*
122 	 * If we're still negotiating with the host cancel the timeout
123 	 * work to not poll the channel twice.
124 	 */
125 	pr_debug("KVP: userspace daemon registered\n");
126 	cancel_delayed_work_sync(&kvp_host_handshake_work);
127 	hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
128 }
129 
130 static void
kvp_register(int reg_value)131 kvp_register(int reg_value)
132 {
133 
134 	struct hv_kvp_msg *kvp_msg;
135 	char *version;
136 
137 	kvp_msg = kzalloc(sizeof(*kvp_msg), GFP_KERNEL);
138 
139 	if (kvp_msg) {
140 		version = kvp_msg->body.kvp_register.version;
141 		kvp_msg->kvp_hdr.operation = reg_value;
142 		strcpy(version, HV_DRV_VERSION);
143 
144 		hvutil_transport_send(hvt, kvp_msg, sizeof(*kvp_msg),
145 				      kvp_register_done);
146 		kfree(kvp_msg);
147 	}
148 }
149 
kvp_timeout_func(struct work_struct * dummy)150 static void kvp_timeout_func(struct work_struct *dummy)
151 {
152 	/*
153 	 * If the timer fires, the user-mode component has not responded;
154 	 * process the pending transaction.
155 	 */
156 	kvp_respond_to_host(NULL, HV_E_FAIL);
157 
158 	hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
159 }
160 
kvp_host_handshake_func(struct work_struct * dummy)161 static void kvp_host_handshake_func(struct work_struct *dummy)
162 {
163 	tasklet_schedule(&kvp_transaction.recv_channel->callback_event);
164 }
165 
kvp_handle_handshake(struct hv_kvp_msg * msg)166 static int kvp_handle_handshake(struct hv_kvp_msg *msg)
167 {
168 	switch (msg->kvp_hdr.operation) {
169 	case KVP_OP_REGISTER:
170 		dm_reg_value = KVP_OP_REGISTER;
171 		pr_info("KVP: IP injection functionality not available\n");
172 		pr_info("KVP: Upgrade the KVP daemon\n");
173 		break;
174 	case KVP_OP_REGISTER1:
175 		dm_reg_value = KVP_OP_REGISTER1;
176 		break;
177 	default:
178 		pr_info("KVP: incompatible daemon\n");
179 		pr_info("KVP: KVP version: %d, Daemon version: %d\n",
180 			KVP_OP_REGISTER1, msg->kvp_hdr.operation);
181 		return -EINVAL;
182 	}
183 
184 	/*
185 	 * We have a compatible daemon; complete the handshake.
186 	 */
187 	pr_debug("KVP: userspace daemon ver. %d connected\n",
188 		 msg->kvp_hdr.operation);
189 	kvp_register(dm_reg_value);
190 
191 	return 0;
192 }
193 
194 
195 /*
196  * Callback when data is received from user mode.
197  */
198 
kvp_on_msg(void * msg,int len)199 static int kvp_on_msg(void *msg, int len)
200 {
201 	struct hv_kvp_msg *message = (struct hv_kvp_msg *)msg;
202 	struct hv_kvp_msg_enumerate *data;
203 	int	error = 0;
204 
205 	if (len < sizeof(*message))
206 		return -EINVAL;
207 
208 	/*
209 	 * If we are negotiating the version information
210 	 * with the daemon; handle that first.
211 	 */
212 
213 	if (kvp_transaction.state < HVUTIL_READY) {
214 		return kvp_handle_handshake(message);
215 	}
216 
217 	/* We didn't send anything to userspace so the reply is spurious */
218 	if (kvp_transaction.state < HVUTIL_USERSPACE_REQ)
219 		return -EINVAL;
220 
221 	kvp_transaction.state = HVUTIL_USERSPACE_RECV;
222 
223 	/*
224 	 * Based on the version of the daemon, we propagate errors from the
225 	 * daemon differently.
226 	 */
227 
228 	data = &message->body.kvp_enum_data;
229 
230 	switch (dm_reg_value) {
231 	case KVP_OP_REGISTER:
232 		/*
233 		 * Null string is used to pass back error condition.
234 		 */
235 		if (data->data.key[0] == 0)
236 			error = HV_S_CONT;
237 		break;
238 
239 	case KVP_OP_REGISTER1:
240 		/*
241 		 * We use the message header information from
242 		 * the user level daemon to transmit errors.
243 		 */
244 		error = message->error;
245 		break;
246 	}
247 
248 	/*
249 	 * Complete the transaction by forwarding the key value
250 	 * to the host. But first, cancel the timeout.
251 	 */
252 	if (cancel_delayed_work_sync(&kvp_timeout_work)) {
253 		kvp_respond_to_host(message, error);
254 		hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
255 	}
256 
257 	return 0;
258 }
259 
260 
process_ob_ipinfo(void * in_msg,void * out_msg,int op)261 static int process_ob_ipinfo(void *in_msg, void *out_msg, int op)
262 {
263 	struct hv_kvp_msg *in = in_msg;
264 	struct hv_kvp_ip_msg *out = out_msg;
265 	int len;
266 
267 	switch (op) {
268 	case KVP_OP_GET_IP_INFO:
269 		/*
270 		 * Transform all parameters into utf16 encoding.
271 		 */
272 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.ip_addr,
273 				strlen((char *)in->body.kvp_ip_val.ip_addr),
274 				UTF16_HOST_ENDIAN,
275 				(wchar_t *)out->kvp_ip_val.ip_addr,
276 				MAX_IP_ADDR_SIZE);
277 		if (len < 0)
278 			return len;
279 
280 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.sub_net,
281 				strlen((char *)in->body.kvp_ip_val.sub_net),
282 				UTF16_HOST_ENDIAN,
283 				(wchar_t *)out->kvp_ip_val.sub_net,
284 				MAX_IP_ADDR_SIZE);
285 		if (len < 0)
286 			return len;
287 
288 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.gate_way,
289 				strlen((char *)in->body.kvp_ip_val.gate_way),
290 				UTF16_HOST_ENDIAN,
291 				(wchar_t *)out->kvp_ip_val.gate_way,
292 				MAX_GATEWAY_SIZE);
293 		if (len < 0)
294 			return len;
295 
296 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.dns_addr,
297 				strlen((char *)in->body.kvp_ip_val.dns_addr),
298 				UTF16_HOST_ENDIAN,
299 				(wchar_t *)out->kvp_ip_val.dns_addr,
300 				MAX_IP_ADDR_SIZE);
301 		if (len < 0)
302 			return len;
303 
304 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.adapter_id,
305 				strlen((char *)in->body.kvp_ip_val.adapter_id),
306 				UTF16_HOST_ENDIAN,
307 				(wchar_t *)out->kvp_ip_val.adapter_id,
308 				MAX_ADAPTER_ID_SIZE);
309 		if (len < 0)
310 			return len;
311 
312 		out->kvp_ip_val.dhcp_enabled =
313 			in->body.kvp_ip_val.dhcp_enabled;
314 		out->kvp_ip_val.addr_family =
315 			in->body.kvp_ip_val.addr_family;
316 	}
317 
318 	return 0;
319 }
320 
process_ib_ipinfo(void * in_msg,void * out_msg,int op)321 static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
322 {
323 	struct hv_kvp_ip_msg *in = in_msg;
324 	struct hv_kvp_msg *out = out_msg;
325 
326 	switch (op) {
327 	case KVP_OP_SET_IP_INFO:
328 		/*
329 		 * Transform all parameters into utf8 encoding.
330 		 */
331 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.ip_addr,
332 				MAX_IP_ADDR_SIZE,
333 				UTF16_LITTLE_ENDIAN,
334 				(__u8 *)out->body.kvp_ip_val.ip_addr,
335 				MAX_IP_ADDR_SIZE);
336 
337 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.sub_net,
338 				MAX_IP_ADDR_SIZE,
339 				UTF16_LITTLE_ENDIAN,
340 				(__u8 *)out->body.kvp_ip_val.sub_net,
341 				MAX_IP_ADDR_SIZE);
342 
343 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.gate_way,
344 				MAX_GATEWAY_SIZE,
345 				UTF16_LITTLE_ENDIAN,
346 				(__u8 *)out->body.kvp_ip_val.gate_way,
347 				MAX_GATEWAY_SIZE);
348 
349 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.dns_addr,
350 				MAX_IP_ADDR_SIZE,
351 				UTF16_LITTLE_ENDIAN,
352 				(__u8 *)out->body.kvp_ip_val.dns_addr,
353 				MAX_IP_ADDR_SIZE);
354 
355 		out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
356 
357 		fallthrough;
358 
359 	case KVP_OP_GET_IP_INFO:
360 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
361 				MAX_ADAPTER_ID_SIZE,
362 				UTF16_LITTLE_ENDIAN,
363 				(__u8 *)out->body.kvp_ip_val.adapter_id,
364 				MAX_ADAPTER_ID_SIZE);
365 
366 		out->body.kvp_ip_val.addr_family = in->kvp_ip_val.addr_family;
367 	}
368 }
369 
370 
371 
372 
373 static void
kvp_send_key(struct work_struct * dummy)374 kvp_send_key(struct work_struct *dummy)
375 {
376 	struct hv_kvp_msg *message;
377 	struct hv_kvp_msg *in_msg;
378 	__u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
379 	__u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
380 	__u32 val32;
381 	__u64 val64;
382 	int rc;
383 
384 	/* The transaction state is wrong. */
385 	if (kvp_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
386 		return;
387 
388 	message = kzalloc(sizeof(*message), GFP_KERNEL);
389 	if (!message)
390 		return;
391 
392 	message->kvp_hdr.operation = operation;
393 	message->kvp_hdr.pool = pool;
394 	in_msg = kvp_transaction.kvp_msg;
395 
396 	/*
397 	 * The key/value strings sent from the host are encoded
398 	 * in utf16; convert it to utf8 strings.
399 	 * The host assures us that the utf16 strings will not exceed
400 	 * the max lengths specified. We will however, reserve room
401 	 * for the string terminating character - in the utf16s_utf8s()
402 	 * function we limit the size of the buffer where the converted
403 	 * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to guarantee
404 	 * that the strings can be properly terminated!
405 	 */
406 
407 	switch (message->kvp_hdr.operation) {
408 	case KVP_OP_SET_IP_INFO:
409 		process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
410 		break;
411 	case KVP_OP_GET_IP_INFO:
412 		/*
413 		 * We only need to pass on the info of operation, adapter_id
414 		 * and addr_family to the userland kvp daemon.
415 		 */
416 		process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
417 		break;
418 	case KVP_OP_SET:
419 		switch (in_msg->body.kvp_set.data.value_type) {
420 		case REG_SZ:
421 			/*
422 			 * The value is a string - utf16 encoding.
423 			 */
424 			message->body.kvp_set.data.value_size =
425 				utf16s_to_utf8s(
426 				(wchar_t *)in_msg->body.kvp_set.data.value,
427 				in_msg->body.kvp_set.data.value_size,
428 				UTF16_LITTLE_ENDIAN,
429 				message->body.kvp_set.data.value,
430 				HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
431 			break;
432 
433 		case REG_U32:
434 			/*
435 			 * The value is a 32 bit scalar.
436 			 * We save this as a utf8 string.
437 			 */
438 			val32 = in_msg->body.kvp_set.data.value_u32;
439 			message->body.kvp_set.data.value_size =
440 				sprintf(message->body.kvp_set.data.value,
441 					"%u", val32) + 1;
442 			break;
443 
444 		case REG_U64:
445 			/*
446 			 * The value is a 64 bit scalar.
447 			 * We save this as a utf8 string.
448 			 */
449 			val64 = in_msg->body.kvp_set.data.value_u64;
450 			message->body.kvp_set.data.value_size =
451 				sprintf(message->body.kvp_set.data.value,
452 					"%llu", val64) + 1;
453 			break;
454 
455 		}
456 
457 		/*
458 		 * The key is always a string - utf16 encoding.
459 		 */
460 		message->body.kvp_set.data.key_size =
461 			utf16s_to_utf8s(
462 			(wchar_t *)in_msg->body.kvp_set.data.key,
463 			in_msg->body.kvp_set.data.key_size,
464 			UTF16_LITTLE_ENDIAN,
465 			message->body.kvp_set.data.key,
466 			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
467 
468 		break;
469 
470 	case KVP_OP_GET:
471 		message->body.kvp_get.data.key_size =
472 			utf16s_to_utf8s(
473 			(wchar_t *)in_msg->body.kvp_get.data.key,
474 			in_msg->body.kvp_get.data.key_size,
475 			UTF16_LITTLE_ENDIAN,
476 			message->body.kvp_get.data.key,
477 			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
478 		break;
479 
480 	case KVP_OP_DELETE:
481 		message->body.kvp_delete.key_size =
482 			utf16s_to_utf8s(
483 			(wchar_t *)in_msg->body.kvp_delete.key,
484 			in_msg->body.kvp_delete.key_size,
485 			UTF16_LITTLE_ENDIAN,
486 			message->body.kvp_delete.key,
487 			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
488 		break;
489 
490 	case KVP_OP_ENUMERATE:
491 		message->body.kvp_enum_data.index =
492 			in_msg->body.kvp_enum_data.index;
493 		break;
494 	}
495 
496 	kvp_transaction.state = HVUTIL_USERSPACE_REQ;
497 	rc = hvutil_transport_send(hvt, message, sizeof(*message), NULL);
498 	if (rc) {
499 		pr_debug("KVP: failed to communicate to the daemon: %d\n", rc);
500 		if (cancel_delayed_work_sync(&kvp_timeout_work)) {
501 			kvp_respond_to_host(message, HV_E_FAIL);
502 			kvp_transaction.state = HVUTIL_READY;
503 		}
504 	}
505 
506 	kfree(message);
507 }
508 
509 /*
510  * Send a response back to the host.
511  */
512 
513 static void
kvp_respond_to_host(struct hv_kvp_msg * msg_to_host,int error)514 kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
515 {
516 	struct hv_kvp_msg  *kvp_msg;
517 	struct hv_kvp_exchg_msg_value  *kvp_data;
518 	char	*key_name;
519 	char	*value;
520 	struct icmsg_hdr *icmsghdrp;
521 	int	keylen = 0;
522 	int	valuelen = 0;
523 	u32	buf_len;
524 	struct vmbus_channel *channel;
525 	u64	req_id;
526 	int ret;
527 
528 	/*
529 	 * Copy the global state for completing the transaction. Note that
530 	 * only one transaction can be active at a time.
531 	 */
532 
533 	buf_len = kvp_transaction.recv_len;
534 	channel = kvp_transaction.recv_channel;
535 	req_id = kvp_transaction.recv_req_id;
536 
537 	icmsghdrp = (struct icmsg_hdr *)
538 			&recv_buffer[sizeof(struct vmbuspipe_hdr)];
539 
540 	if (channel->onchannel_callback == NULL)
541 		/*
542 		 * We have raced with util driver being unloaded;
543 		 * silently return.
544 		 */
545 		return;
546 
547 	icmsghdrp->status = error;
548 
549 	/*
550 	 * If the error parameter is set, terminate the host's enumeration
551 	 * on this pool.
552 	 */
553 	if (error) {
554 		/*
555 		 * Something failed or we have timed out;
556 		 * terminate the current host-side iteration.
557 		 */
558 		goto response_done;
559 	}
560 
561 	kvp_msg = (struct hv_kvp_msg *)
562 			&recv_buffer[sizeof(struct vmbuspipe_hdr) +
563 			sizeof(struct icmsg_hdr)];
564 
565 	switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
566 	case KVP_OP_GET_IP_INFO:
567 		ret = process_ob_ipinfo(msg_to_host,
568 				 (struct hv_kvp_ip_msg *)kvp_msg,
569 				 KVP_OP_GET_IP_INFO);
570 		if (ret < 0)
571 			icmsghdrp->status = HV_E_FAIL;
572 
573 		goto response_done;
574 	case KVP_OP_SET_IP_INFO:
575 		goto response_done;
576 	case KVP_OP_GET:
577 		kvp_data = &kvp_msg->body.kvp_get.data;
578 		goto copy_value;
579 
580 	case KVP_OP_SET:
581 	case KVP_OP_DELETE:
582 		goto response_done;
583 
584 	default:
585 		break;
586 	}
587 
588 	kvp_data = &kvp_msg->body.kvp_enum_data.data;
589 	key_name = msg_to_host->body.kvp_enum_data.data.key;
590 
591 	/*
592 	 * The windows host expects the key/value pair to be encoded
593 	 * in utf16. Ensure that the key/value size reported to the host
594 	 * will be less than or equal to the MAX size (including the
595 	 * terminating character).
596 	 */
597 	keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
598 				(wchar_t *) kvp_data->key,
599 				(HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
600 	kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */
601 
602 copy_value:
603 	value = msg_to_host->body.kvp_enum_data.data.value;
604 	valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
605 				(wchar_t *) kvp_data->value,
606 				(HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
607 	kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */
608 
609 	/*
610 	 * If the utf8s to utf16s conversion failed; notify host
611 	 * of the error.
612 	 */
613 	if ((keylen < 0) || (valuelen < 0))
614 		icmsghdrp->status = HV_E_FAIL;
615 
616 	kvp_data->value_type = REG_SZ; /* all our values are strings */
617 
618 response_done:
619 	icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
620 
621 	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
622 				VM_PKT_DATA_INBAND, 0);
623 }
624 
625 /*
626  * This callback is invoked when we get a KVP message from the host.
627  * The host ensures that only one KVP transaction can be active at a time.
628  * KVP implementation in Linux needs to forward the key to a user-mde
629  * component to retrieve the corresponding value. Consequently, we cannot
630  * respond to the host in the context of this callback. Since the host
631  * guarantees that at most only one transaction can be active at a time,
632  * we stash away the transaction state in a set of global variables.
633  */
634 
hv_kvp_onchannelcallback(void * context)635 void hv_kvp_onchannelcallback(void *context)
636 {
637 	struct vmbus_channel *channel = context;
638 	u32 recvlen;
639 	u64 requestid;
640 
641 	struct hv_kvp_msg *kvp_msg;
642 
643 	struct icmsg_hdr *icmsghdrp;
644 	int kvp_srv_version;
645 	static enum {NEGO_NOT_STARTED,
646 		     NEGO_IN_PROGRESS,
647 		     NEGO_FINISHED} host_negotiatied = NEGO_NOT_STARTED;
648 
649 	if (kvp_transaction.state < HVUTIL_READY) {
650 		/*
651 		 * If userspace daemon is not connected and host is asking
652 		 * us to negotiate we need to delay to not lose messages.
653 		 * This is important for Failover IP setting.
654 		 */
655 		if (host_negotiatied == NEGO_NOT_STARTED) {
656 			host_negotiatied = NEGO_IN_PROGRESS;
657 			schedule_delayed_work(&kvp_host_handshake_work,
658 				      HV_UTIL_NEGO_TIMEOUT * HZ);
659 		}
660 		return;
661 	}
662 	if (kvp_transaction.state > HVUTIL_READY)
663 		return;
664 
665 	if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 4, &recvlen, &requestid)) {
666 		pr_err_ratelimited("KVP request received. Could not read into recv buf\n");
667 		return;
668 	}
669 
670 	if (!recvlen)
671 		return;
672 
673 	/* Ensure recvlen is big enough to read header data */
674 	if (recvlen < ICMSG_HDR) {
675 		pr_err_ratelimited("KVP request received. Packet length too small: %d\n",
676 				   recvlen);
677 		return;
678 	}
679 
680 	icmsghdrp = (struct icmsg_hdr *)&recv_buffer[sizeof(struct vmbuspipe_hdr)];
681 
682 	if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
683 		if (vmbus_prep_negotiate_resp(icmsghdrp,
684 				recv_buffer, recvlen,
685 				fw_versions, FW_VER_COUNT,
686 				kvp_versions, KVP_VER_COUNT,
687 				NULL, &kvp_srv_version)) {
688 			pr_info("KVP IC version %d.%d\n",
689 				kvp_srv_version >> 16,
690 				kvp_srv_version & 0xFFFF);
691 		}
692 	} else if (icmsghdrp->icmsgtype == ICMSGTYPE_KVPEXCHANGE) {
693 		/*
694 		 * recvlen is not checked against sizeof(struct kvp_msg) because kvp_msg contains
695 		 * a union of structs and the msg type received is not known. Code using this
696 		 * struct should provide validation when accessing its fields.
697 		 */
698 		kvp_msg = (struct hv_kvp_msg *)&recv_buffer[ICMSG_HDR];
699 
700 		/*
701 		 * Stash away this global state for completing the
702 		 * transaction; note transactions are serialized.
703 		 */
704 
705 		kvp_transaction.recv_len = recvlen;
706 		kvp_transaction.recv_req_id = requestid;
707 		kvp_transaction.kvp_msg = kvp_msg;
708 
709 		if (kvp_transaction.state < HVUTIL_READY) {
710 			/* Userspace is not registered yet */
711 			kvp_respond_to_host(NULL, HV_E_FAIL);
712 			return;
713 		}
714 		kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
715 
716 		/*
717 		 * Get the information from the
718 		 * user-mode component.
719 		 * component. This transaction will be
720 		 * completed when we get the value from
721 		 * the user-mode component.
722 		 * Set a timeout to deal with
723 		 * user-mode not responding.
724 		 */
725 		schedule_work(&kvp_sendkey_work);
726 		schedule_delayed_work(&kvp_timeout_work,
727 					HV_UTIL_TIMEOUT * HZ);
728 
729 		return;
730 
731 	} else {
732 		pr_err_ratelimited("KVP request received. Invalid msg type: %d\n",
733 				   icmsghdrp->icmsgtype);
734 		return;
735 	}
736 
737 	icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
738 		| ICMSGHDRFLAG_RESPONSE;
739 
740 	vmbus_sendpacket(channel, recv_buffer,
741 			 recvlen, requestid,
742 			 VM_PKT_DATA_INBAND, 0);
743 
744 	host_negotiatied = NEGO_FINISHED;
745 	hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
746 }
747 
kvp_on_reset(void)748 static void kvp_on_reset(void)
749 {
750 	if (cancel_delayed_work_sync(&kvp_timeout_work))
751 		kvp_respond_to_host(NULL, HV_E_FAIL);
752 	kvp_transaction.state = HVUTIL_DEVICE_INIT;
753 }
754 
755 int
hv_kvp_init(struct hv_util_service * srv)756 hv_kvp_init(struct hv_util_service *srv)
757 {
758 	recv_buffer = srv->recv_buffer;
759 	kvp_transaction.recv_channel = srv->channel;
760 	kvp_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 4;
761 
762 	/*
763 	 * When this driver loads, the user level daemon that
764 	 * processes the host requests may not yet be running.
765 	 * Defer processing channel callbacks until the daemon
766 	 * has registered.
767 	 */
768 	kvp_transaction.state = HVUTIL_DEVICE_INIT;
769 
770 	hvt = hvutil_transport_init(kvp_devname, CN_KVP_IDX, CN_KVP_VAL,
771 				    kvp_on_msg, kvp_on_reset);
772 	if (!hvt)
773 		return -EFAULT;
774 
775 	return 0;
776 }
777 
hv_kvp_cancel_work(void)778 static void hv_kvp_cancel_work(void)
779 {
780 	cancel_delayed_work_sync(&kvp_host_handshake_work);
781 	cancel_delayed_work_sync(&kvp_timeout_work);
782 	cancel_work_sync(&kvp_sendkey_work);
783 }
784 
hv_kvp_pre_suspend(void)785 int hv_kvp_pre_suspend(void)
786 {
787 	struct vmbus_channel *channel = kvp_transaction.recv_channel;
788 
789 	tasklet_disable(&channel->callback_event);
790 
791 	/*
792 	 * If there is a pending transtion, it's unnecessary to tell the host
793 	 * that the transaction will fail, because that is implied when
794 	 * util_suspend() calls vmbus_close() later.
795 	 */
796 	hv_kvp_cancel_work();
797 
798 	/*
799 	 * Forece the state to READY to handle the ICMSGTYPE_NEGOTIATE message
800 	 * later. The user space daemon may go out of order and its write()
801 	 * may fail with EINVAL: this doesn't matter since the daemon will
802 	 * reset the device by closing and re-opening it.
803 	 */
804 	kvp_transaction.state = HVUTIL_READY;
805 	return 0;
806 }
807 
hv_kvp_pre_resume(void)808 int hv_kvp_pre_resume(void)
809 {
810 	struct vmbus_channel *channel = kvp_transaction.recv_channel;
811 
812 	tasklet_enable(&channel->callback_event);
813 
814 	return 0;
815 }
816 
hv_kvp_deinit(void)817 void hv_kvp_deinit(void)
818 {
819 	kvp_transaction.state = HVUTIL_DEVICE_DYING;
820 
821 	hv_kvp_cancel_work();
822 
823 	hvutil_transport_destroy(hvt);
824 }
825